The report, coauthored by Matin Qaim of the Center of Development Research in Bonn, Germany, found that the BT cotton needed to be sprayed with only 30 percent of the pesticide used on its natural neighbors to keep bollworms away.

The University of Arkansas Division of Agriculture said soybean-eating bollworms have flourished because pesticide evaporates in the heat instead of getting under the bean plants 'canopy where the worms do their damage.